Energy
What is energy? Energy is the ability to do work Work is a transfer of energy If you lift a box you do work, this work requires energy 2 main types of energy: Kinetic and Potential Units are Joules!
Kinetic energy KE depends on mass and speed on the object KE= ½ mv2 Tailgaters Pg 448: 1-3
Potential energy Energy that is stored due to position Gravitational PE is due to height and (g=9.8) PE= mgh Cliff diving
Elastic Potential Energy Energy of an object that is stretched or compressed Ex. Rubber band, springs, bouncing ball
Other forms of energy Mechanical energy- sum of an object’s potential and kinetic energy PE+KE=ME Thermal Energy- heat energy, if hot enough they emit visible light Chemical Energy- energy stored in chemical bonds Ex. Burning wood or gas
More forms of energy Sound energy- waves carry energy, you can feel sound Electrical energy- energy associated with electric charges Electromagnetic energy- waves that travel through space, EM Spectrum Nuclear energy- energy stored in atomic nuclei
Energy Conversion and Conservation
Energy Conversion Energy can be converted from one form to another Ex. Pendulum to the face Striking a match microwave
Conservation of Energy Energy can’t be created or destroyed Why then does a car stop moving if you let it coast? Pool balls colliding Pendulum
Energy Conversions PE turns into KE as an object falls PE and KE are constantly changing Pendulums Pole vaulting
Energy Conversion Calculations Initial (KE+PE) = final (KE+PE) Pg 458: 1-3
Energy and Mass E=mc2 Energy and mass are equivalent and can be turned into one another A tiny amount of matter creates a tremendous amount of energy 1 g of TNT 2931J Cold fusion
Class Work Pg 459: 7-10
1. Design a roller coaster and explain all parts of it where there is an energy transfer or conversion. 2.ME, PE, KE, Friction, Sound, Heat all need to be included in the coaster somewhere 3. Draw a picture and color it, and name it